A brain tumor is a localized intracranial lesion that occupies space within the skull. Primary brain tumors originate from cells and structures within the brain. Secondary, or metasta-tic, brain tumors develop from structures outside the brain (lung, breast, lower gastrointestinal tract, pancreas, kidney, and skin [melanomas]) and occur in 10% to 20% of all can-cer patients. The highest incidence of brain tumors in adults occurs between the fifth and seventh decades. Brain tumors rarely metastasize outside the central nervous system but cause 100 Brain Tumors
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Brain Tumors 101 death by impairing vital functions (respiration) or by increas-
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ing the ICP. Brain tumors may be classified into several groups:
those arising from the coverings of the brain (eg, dural menin-gioma), those developing in or on the cranial nerves (eg, acoustic neuroma), those originating within brain tissue (eg, glioma), and metastatic lesions originating elsewhere in the body. Tumors of the pituitary and pineal glands and of cere-bral blood vessels are also types of brain tumors. Tumors may be benign or malignant. A benign tumor may occur in a vital area and have effects as serious as a malignant tumor.
Types of Tumors
• Gliomas, the most common brain neoplasms, cannot be totally removed without causing damage, because they spread by infiltrating into the surrounding neural tissue.
• Meningiomas are common benign encapsulated tumors of arachnoid cells on the meninges. They are slow growing and occur most often in middle-aged women.
• An acoustic neuroma is a tumor of the eighth cranial nerve (hearing and balance). It may grow slowly and attain con-siderable size before it is correctly diagnosed.
• Pituitary adenomas may cause symptoms as a result of pres-sure on adjacent structures or hormonal changes such as hyperfunction or hypofunction of the pituitary.
• Angiomas are masses composed largely of abnormal blood vessels and are found in or on the surface of the brain; they may never cause symptoms, or they may give rise to symp-toms of brain tumor. The walls of the blood vessels in angiomas are thin, increasing the risk for hemorrhagic stroke.
Clinical Manifestations Increased ICP
• Headache, although not always present, is most common in the early morning and is made worse by coughing, straining, or sudden movement. Headaches are usually described as deep, expanding, or dull but unrelenting. Frontal tumors produce a bilateral frontal headache; pituitary gland tumors produce bitemporal pain; in cerebellar tumors, the headache may be located in the suboccipital region at the back of the head.
• Vomiting, seldom related to food intake, is usually due to irritation of the vagal centers in the medulla.
• Papilledema (edema of the optic nerve) is associated with visual disturbances.
• Personality changes and a variety of focal deficits, including motor, sensory, and cranial nerve dysfunction, are common.
Localized Symptoms
The progression of the signs and symptoms is important because it indicates tumor growth and expansion. The most common focal or localized symptoms are hemiparesis, seizures, and mental status changes.
• Tumor of the motor cortex: seizurelike movements localized to one side of the body (Jacksonian seizures)
• Occipital lobe tumors: visual manifestations, such as con-tralateral homonymous hemianopsia (visual loss in half of the visual field on the opposite side of tumor) and visual hallucinations
• Tumors of the cerebellum: dizziness; an ataxic or staggering gait, with tendency to fall toward side of lesion; marked muscle incoordination; and nystagmus)
• Tumors of the frontal lobe: personality disorders, changes in emotional state and behavior, and an apathetic mental atti-tude
• Tumors of the cerebellopontine angle: usually originate in sheath of acoustic nerve; tinnitus and vertigo, then pro-gressive nerve deafness (eighth cranial nerve dysfunction);
staggering gait, numbness and tingling of the face and tongue, progressing to weakness and paralysis of the face;
abnormalities in motor function may be present Assessment and Diagnostic Methods
• History of the illness and manner in which symptoms evolved
• Neurologic examination indicating areas involved
• CT, MRI, positron emission tomography (PET), computer-assisted stereotactic (three-dimensional) biopsy, cerebral angiography, EEG, and cytologic studies of the cerebrospinal fluid
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Brain Tumors 103 Medical Management
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A variety of medical treatments, including chemotherapy and external-beam radiation therapy, are used alone or in combi-nation with surgical resection.
Surgical Management
The objective of surgical management is to remove or destroy the entire tumor without increasing the neurologic deficit (paralysis, blindness) or to relieve symptoms by partial removal (decompression). A variety of treatment modalities may be used; the specific approach depends on the type of tumor, its location, and its accessibility. In many patients, combinations of these modalities are used.
Other Therapies
• Radiation therapy (the cornerstone of treatment for many brain tumors)
• Brachytherapy (the surgical implantation of radiation sources to deliver high doses at a short distance)
• IV autologous bone marrow transplantation for marrow tox-icity associated with high doses of drugs and radiation
• Gene-transfer therapy (currently being tested) Nursing Management
• Evaluate gag reflex and ability to swallow preoperatively.
• Teach patient to direct food and fluids toward the unaffected side. Assist patient to an upright position to eat, offer a semi-soft diet, and have suction readily available if gag response is diminished.
• Reassess function postoperatively.
• Perform neurologic checks, monitor vital signs, and main-tain a neurologic flow chart. Space nursing interventions to prevent rapid increase in ICP.
• Reorient patient when necessary to person, time, and place.
Use orienting devices (personal possessions, photographs, lists, clock). Supervise and assist with self-care. Monitor and intervene to prevent injury.
• Monitor patients with seizures.
• Check motor function at intervals; assess sensory distur-bances.
• Evaluate speech.
• Assess eye movement, pupil size, and reaction.
For more information, see Chapter 65 in Smeltzer, S. C., Bare, B. G., Hinkle, J. L., & Cheever, K. H. (2010). Brunner and Suddarth’s textbook of medical-surgical nursing (12th ed.). Philadelphia:
Lippincott Williams & Wilkins.